At present, touch technology is used extensively in various electronic products. Broadly, working of touch devices may be categorized into two types of touch technologies. The two types of the touch technologies are capacitive touch recognition technology and pressure sensitive touch recognition technology (also known as resistive touch technology). In resistive touch panels, touch surfaces of the touch panels are pressed to drive upper and lower conductive films to be in contact with each other to detect touch event. On the other hand, capacitive touch panels are gently touched by a user's finger to produce a change of capacitance between the user's finger and the capacitive touch panel, which is recognized as a touch event.
Generally, the capacitive touch panels have a better sensitivity on the control or operation than that of the resistive touch panels. In addition, the capacitive touch panels have the advantages of dustproof, fire-resisting, scratch-resisting, high resolution, high transmittance, low reflection, high contrast, good durability, multi-point touch control and gesture operation over the resistive touch panels, and thus manufacturers attempt to adopt and develop related capacitive touch panel products.
With reference to FIG. 1 for a conventional capacitive touch panel 91, a user of the capacitive touch panel 91 controls a virtual keyboard 93 of the capacitive touch panel 91 by using a pulp of a finger 92. During the operation, the finger 92 blocks a portion of the user's vision, and the pulp of the finger 92 has a relatively large area which may touch other areas easily and by mistake and may cause unexpected operation frequently, particularly for users with have bigger fingers.
In addition, a nail 94 of the finger 92 is a non-conductor, so that the nail 94 cannot produce an appropriate capacitance with the capacitive touch panel 91 for controlling and operating the capacitive touch panel 91. Therefore, users with long nails have difficulties of operating the capacitive touch panel 91.
In addition, the finger may be contaminated easily, particularly in the hot weather, and thus giving rise to the issue of having sweat on the user's hands, and stains may remain on the capacitive touch panel 91 that is frequently touched by the finger 92. Therefore, it is difficult to keep the capacitive touch panel 91 clean all the time. Also, it is desirable to produce appropriate capacitance in the touch panel 91 to improve control and operation of the capacitive touch panels.
At present, the technology of using the finger 92 to operate and control the capacitive touch panel 91 have many problems that require breakthroughs and solutions.
Some prior arts try to address the aforementioned problems by providing a touch pen having means to prevent damage to a touch panel by absorbing total pressure applied on touch surface of the touch panel. These prior arts use a spring like mechanism for absorbing extra pressure applied on the touch surface by the tip of the touch pens. For example, Japanese Utility Model Application published as JP9282098 (A) on Oct. 31, 1997 discloses a technique in which a spring is integrally formed on an end-part of a touch pen's tip. Further, when the touch pen touches a touch panel, the touch pen's tip slides in the longitudinal direction of the touch pen into an opening, to absorb total pressure applied on the touch surface of the touch panel. Hence, this technique reduces the chances of causing damage to the touch panel. However, the touch pen disclosed in JP9282098 (A) does not facilitate the production of appropriate capacitance in the capacitive touch panels.
Further, U.S. patent application, published with Publication No. U.S.20010028345A1 (later, U.S. Pat. No. 6,710,267), assigned to International Business Machines Corporation, discloses techniques that enable a touch pen to provide a smooth usage experience to its user on a touch panel, without causing any flaw in the touch panel. The touch pen disclosed in the U.S. patent application uses a touch ball made of resin like material at a pen tip of an input pen. The touch ball is held via two springs. Further, the touch ball is designed to be softer than a screen of a touch panel. This arrangement suppresses any deformation of the soft touch ball even if the input pen is strongly pressed against a screen of a touch panel. However, the touch pen disclosed in U.S.20010028345A1 does not facilitate the production of appropriate capacitance in the capacitive touch panels.
Furthermore, U.S. Pat. No. 6,361,232, assigned to Pilot Precision Kabushiki Kaisha, discloses techniques that enable a touch pen to avoid breaking a touch panel, in case if an excessively high force is exerted on the input tip of the touch pen. The input pen can be pressed against a touch panel of a portable information processing terminal device to enter desired data into the portable information processing terminal device. Thus, the input pen can be utilized to provide inputs to the touch panel and includes a mechanism that prevents damages to the touch sensitive surface of a device. However, there is no teaching provided by the patent for enabling a touch pen to produce appropriate capacitance in capacitive touch panels to improve control and operation of the capacitive touch panels.
Another existing technique as disclosed in U.S. patent application, published with Publication No. 20120026127, assigned to Samsung Mobile Display Co. Ltd., discloses techniques that enable a stylus pen for a capacitive touch panel to perform precise input while stably transmitting touch input. Further, the patent discloses a technique that enables the stylus pen to provide sufficient capacitance change that is enough to sense touch input by ensuring a contact area with a touch screen, by connecting a transparent electrode plate having a larger cross-sectional area than a center conductor at a tip portion of the center conductor. However, there in no teaching provided by this application for user's selection of a larger touch area or smaller touch area.
In light of the foregoing, there is a need for a touch device, such as touch pen, that can perform efficiently on touch sensitive screens, while maintaining a clean capacitive touch panel.